What are the active volcanoes in Hawaii and what is their status?

Kilauea is considered one of the worlds most frequently active volcanoes. If you just look at the number of Kilauea eruptions recorded since Europeans arrived, there have been 62 eruptions in 245 years, which comes out to 1 eruption every 3.95 years. However, this completely ignores the fact that some of the eruptions lasted a long time. For example, the current eruption started in January of 1983 and has been continuous ever since! Likewise, there was an active lava lake in the summit caldera from at least 1823 until 1924, while at the same time eruptions would take place elsewhere on the flanks of the volcano.

Mauna Loa is an active volcano and is due for an eruption. Mauna Loa has erupted 15 times since 1900. These eruptions have lasted from a few hours to 145 days. Since 1950 Mauna Loa has erupted only twice, in 1975 and 1984. The 1975 eruption lasted 1 day. The 1984 eruption lasted 3 weeks. Nearly all the eruptions begin at the summit. About half of these migrate down into a rift zone.

Haleakala began growing on the ocean floor roughly 1-2 million years ago. It erupted most recently in 1790 at La Perouse Bay.

Hualalai is an active volcano. The resort town of Kailua is on the southwest flank of the volcano. Hualalai last erupted in 1801 and sent lava from a vent on its northeast rift down to the ocean. Swarms of earthquakes in 1929 were probably the result of magma movement within the volcano but there was not an eruption. Hualalai is monitored by geologists of the U.S. Geological Survey’s Hawaiian Volcano Observatory. In the last 24 years there have been no swarms of microearthquakes nor any harmonic tremor. Since the early 1980’s the geologists have been surveying the volcano. Hualalai is not expanding at the present time nor has expanded since the geologists began making their measurements. If anything changes I’m sure we’ll hear about it.

Lo’ihi means “long one”, a reference to its elongate shape. For a 3-d image, check out the Hawaii Undersea Geological Observatory (HUGO) home. Right now, the summit of Lo’ihi is about 970 meters below sea level. It is growing on the lower flanks of its two neighbors, Kilauea and Mauna Loa, with its base at a depth of about 4000 meters below sea level, so you can say that Lo’ihi itself is about 3000 m high. We don’t really know when it will reach the surface or even if it will. There is an underwater volcano off the NW coast of the big island of Hawai’i named Mahukona, and there is debate about whether it ever grew above sea level, or died out prior to doing so. The most often-heard time required for Lo’ihi to reach sea level is about 10,000 years, but that is really only a guess. It might be 30,000 years for all we know. It is far enough away from the coastline of Hawai’i that I imagine that at first it will be a separate island when it breaks the surface. As it grows (and especially if Kilauea and Mauna Loa are still erupting) it will soon be joined to the island.